Rejection reason sets sales order item to not relevant for billing

What causes this issue?

The customer has not yet been fully invoiced for the quantity delivered
by the supplier. However, as the "Not Relevant for Billing" indicator
was configured for the specified rejection reason, it is no longer
possible to create billing documents for the customer once the sales
order item has been rejected.

System Response

INCLUDE VA_CONFIG_MSG_SYSTEMRESPONSE OBJECT DOKU ID TX

How to fix this error?

If appropriate, choose a rejection reason for which the "Not Relevant
for Billing" indicator is not set.
If the selected rejection reason fits your business rules, check whether
you want to fully invoice the customer for the quantity delivered by the
supplier before you reject the sales order item. If this message is an
error message, full further invoicing must take place for the selected
rejection reason.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.